MySQL IFNULL "N/A" "cannot be found in the collection project" error-CodePudding

I've been using IFNULL function in the my SQL query from a NULL value is zero, as shown in the following:

The SELECT IFNULL (mem.com ment_count, 0) FROM members...

This is very good. I now are trying to use IFNULL function converts A NULL value to A string "N/A", but I continue to receive the error: "in the name of the request or serial number not found in the corresponding collection project" :

The SELECT IFNULL (mem) address2, 'N/A') FROM members...

I don't even try to use COALESCE only because it is an empty string instead of NULL:

The SELECT COALESCE (NULLIF (mem) address2, ' '), 'N/A') FROM members...

But still sell the same error.
If you have any idea?

CodePudding user response:

Your query is very good, but your code may be looking for the column name? Try alias:

The SELECT IFNULL (mem) address2, 'N/A) AS address2 FROM members mem...

CodePudding user response:

Can be solved with the Max and min